U.S. patent number 4,322,976 [Application Number 06/137,551] was granted by the patent office on 1982-04-06 for mechanical vibration analyzer.
This patent grant is currently assigned to IRD Mechanalysis, Inc.. Invention is credited to Edwin D. Sisson, Donn V. Stoutenburg, Glen H. Thomas.
United States Patent |
4,322,976 |
Sisson , et al. |
April 6, 1982 |
Mechanical vibration analyzer
Abstract
A visual graphical display of instantaneous mechanical vibration
versus frequency over a selected frequency spectrum is presented to
provide a vibration analyst with a prompt overall visual impression
of the mechanical vibration characteristics of a rotating device
which is under surveillance. In an alternative application, the
visual display permits a rapid adjustment of an electrical bandpass
filter of an associated vibration analyzer. The device employs
several trains of diodes which are arranged so that one or more
diode in each train is illuminated at any one moment.
Inventors: |
Sisson; Edwin D. (Worthington,
OH), Stoutenburg; Donn V. (Westerville, OH), Thomas; Glen
H. (Worthington, OH) |
Assignee: |
IRD Mechanalysis, Inc.
(Columbus, OH)
|
Family
ID: |
22477942 |
Appl.
No.: |
06/137,551 |
Filed: |
April 4, 1980 |
Current U.S.
Class: |
73/659;
324/76.13; 702/43 |
Current CPC
Class: |
G01H
3/08 (20130101); G01N 3/32 (20130101); G01N
2291/02827 (20130101) |
Current International
Class: |
G01N
3/32 (20060101); G01H 3/08 (20060101); G01H
3/00 (20060101); G01N 029/04 () |
Field of
Search: |
;73/659,660,579
;324/77A,77B,77E,77G ;340/715,753,754,766 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
3029385 |
April 1962 |
Steinbrenner et al. |
|
Other References
Henry, "An LED-Readout Audio Power Meter", Popular Electronics,
Mar. 1976, pp. 35-38..
|
Primary Examiner: Ciarlante; Anthony V.
Attorney, Agent or Firm: Mueller and Smith
Claims
We claim:
1. A vibration analyzer comprising:
vibration detector means for converting mechanical vibrations into
a corresponding cyclic electrical signal;
an electrical filter having an input for receiving said electrical
signal and manually actuable for tuning within a wide range of
electrical frequencies to select narrow band portions thereof for
submittal at an output;
electrical circuit means having an input and including a visual
readout for observing amplitude and frequency values within a said
narrow band portion of said range of electrical frequencies
selected by said filter actuation;
a visible display comprised of a plurality of light emitting diode
trains mutually disposed in parallel adjacency to provide a
spectral readout of amplitude and frequency substantially for said
wide range of electrical frequencies;
a plurality of octave filters each selecting a unique band of said
frequencies within said wide range thereof;
each said train of light emitting diodes corresponding to and
responsive to one of said octave filters and each said train
including means for illuminating at least one unique diode in the
train corresponding to the instantaneous amplitude of said selected
unique frequency band; and
switch means for coupling said plurality of octave filters to
receive said electrical signal and alternately for coupling said
circuit means input and said plurality of octave filters with said
filter output.
2. The vibration analyzer of claim 1 wherein a single one of the
said diodes in each of said diode trains is illuminated at any
instant.
3. The vibration analyzer of claim 1 wherein a single one or a pair
of adjacent ones of the diodes in each train is illuminated at any
instant.
4. The vibration analyzer of claim 1 wherein each diode in each
train is illuminated only when all of the diodes below it in the
same train are illuminated.
5. The improvement of claim 1 wherein each of the said octave
filters is adapted to select electrical frequencies substantially
within a fractional portion of a frequency octave.
6. The vibration analyzer of claim 1 in which said switch means
simultaneously couples said circuit means input to receive said
electrical signal when coupling said plurality of active filters to
receive said electrical signal.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improvement in mechanical
vibration analyzers and more particularly to a mechanical vibration
analyzer which includes a "quik-look" visible display octave
analyzer.
2. Description of the Prior Art
Mechanical vibration analyzers are well-known. See U.S. Pat. Nos.
2,711,647, 3,205,713 and 3,938,394. Octave band analyzers and
fractional octave band analyzers are well-known in the electronics
industry as devices for instantaneously observing the relative wave
energy content of a multi-frequency wave phenomenon, e.g., an
acoustical signal.
In the past, mechanical vibration analyzer equipment has included a
mechanical vibration detector which converts instantaneous
mechanical vibrations into corresponding cyclic electrical signals
having wave components at multiple electrical frequencies. The
vibration analyzers also include narrow band electrical filters for
selecting various electrical frequency components within a narrow
range of frequencies. The instantaneous amplitude of the electrical
wave signals within the narrow filter band is observed. For
example, the amplitude of the narrow band electrical signals is
displayed in a voltmeter scale which may be suitably calibrated to
indicate the corresponding mechanical vibration values, such as
displacement, velocity, acceleration.
By employing variable frequency band filters in prior art
mechanical vibration analyzers, it is possible for the operator to
scan through multiple frequency ranges and observe the
instantaneous mechanical vibration amplitude in each observed
frequency range. This is time-consuming, particularly at lower
frequencies where the electrical filter components require
substantial time lapse to achieve equilibrium conditions. At any
one instant, the prior art devices display only the amplitude
existing for the particular frequency band selected by the
operator. If the operator is seeking peak amplitude phenomena, it
may be necessary for the operator to conduct a frequency scan over
the entire spectrum of frequencies which the mechanical vibration
analyzer is capable of observing.
Accordingly it would be desirable to have a mechanical vibration
analyzer which can supply a qualitative indication to the operator
of the instantaneous mechanical vibration amplitudes in various
frequency bands over the range of vibration frequencies which the
analyzer is capable of observing. The operator thereby can quickly
and effectively target the range of vibration frequencies which
should be subjected to more intensive observation in the analyzer
equipment.
Recent developments in vibration analyzers having digital readout
presentations have created a difficulty in fine tuning the analyzer
filters. Prior art analyzers have meter-deflection readout
presentations providing a useful fine tuning indicator for the
analyzer filters. See U.S. Pat. No. 3,228,235. The operator could
easily detect peak deflections and thereby fine tune the
filter.
A buckets and arrows technique has been described in copending U.S.
patent application Ser. No. 76,030, filed Sept. 17, 1979, which
requires supplementary apparatus for the fine tuning function in
vibration analyzers having digital readout presentations.
A quick visual fine tuning device for an analyzer filter would be
desirable in a vibration analyzer having a digital readout
display.
SUMMARY OF THE INVENTION
The present invention is an improvement in prior art mechanical
vibration analyzer equipment of the type which includes
(1) a vibration detector for converting mechanical vibrations into
a corresponding cyclic electrical signal;
(2) an electrical filter for selecting narrow band portions of the
electrical wave components of the cyclic electrical signal; and
(3) electrical circuit means for observing a selected narrow band
portion of the cyclic electrical signal.
According to this improvement, the cyclic electrical signal is
applied to the electrical input terminal of an octave band analyzer
which has a visible display formed from a series of parallel diode
trains and has multiple filter means, one each for each of the
parallel diode trains whereby the cyclic electrical signal can be
filtered into a series of selected frequency band components and
the amplitude of each of the selective portions can be visibly
displayed on the related one of the parallel diode trains.
Accordingly the operator of the vibration analyzer can visibly
observe the overall nature of the mechanical vibrations throughout
the spectrum of frequencies covered by the octave band
analyzer.
This improvement also functions as a fine tuning device for the
filter of a vibration analyzer which has a digital readout
presentation. The filter is connected in series with the octave
band analyzer. The output signal from the filter will illuminate
one or perhaps two of the parallel diode trains of the octave band
analyzer. The operator can easily fine tune the filter by observing
the peak response in the appropriate one of the diode trains.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration showing a prior art mechanical
vibration analyzer installation to which the present improvement
has been incorporated;
FIGS. 2, 3, 4 are plan views of typical visible displays resulting
from the present equipment.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
As shown in FIG. 1, the prior art mechanical vibration analyzer
installations are applied to sources of cyclic mechanical vibration
such as a rotor 10. The cyclic mechanical vibrations of the rotor
10 are detected by a vibration detector 11 and delivered through a
conductor 12 to a signal conditioner 13 which develops an output
signal in the conductor 14 corresponding to the instantaneous
mechanical vibrations of the rotor 10. The conductor 14 is
connected to a narrow band filter 15 which selects those electrical
frequency components of the cyclic electrical signal within a
selected band of frequencies and delivers those electrical signal
components through a conductor 16, a switch 17 and a conductor 18
to an analyzer 19 which frequently includes a voltmeter 20 suitably
calibrated in units corresponding to the mechanical vibration of
the rotor 10.
The vibration detector 11 can be responsive to the instantaneous
displacement of the rotor 10 or to the instantaneous velocity of
the rotor 10 or to the instantaneous acceleration of the rotor 10.
Depending upon which phenomenon of the mechanical vibration is
observed by the detector 11, the signal conditioner 13 will convert
the electrical signal into a useful form for the filter 15 and
analyzer 19, e.g., an acceleration-related signal can be integrated
once to the corresponding velocity-related signal or integrated
twice to the corresponding displacement signal.
According to the present invention an octave band analyzer 21 is
connected through a conductor 22 to the base of switch 17. The
switch 17 has a switch arm 17c which contacts either terminal 17b
or 17a. When the switch arm 17c contacts terminal 17a, the filter
15 is connected in series with the analyzer 19 and also in series
with the octave band analyzer 21. When the switch arm 17c contacts
terminal 17b, the filter 15 is bypassed through conductor 26. The
vibration signal is delivered directly from the signal conditioner
13 through conductor 14, conductor 26, switch 17, conductor 18 to
the analyzer 19 and also through the conductor 22 to the octave
band analyzer 21.
The octave band analyzer 21 includes a matrix 23 of individual
diodes 25 which are aligned in trains labeled A, B, C, D, E, F, G
and in rows labeled 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20.
For each of the diode chains A, B, C, D, E, F, G there is an octave
filter 24 which receives the cyclic electrical signal from the
conductor 22 and delivers those selected frequency components of
that signal to the train of diodes 22 through circuitry which
illuminates one or more of the diodes 25 in each train.
Each of the octave band filters 24 is selected to pass a selected
frequency of electrical wave components drawn from the cyclic
electrical signal. Conveniently, the selected frequency bands
differ by one octave or by an aliquot portion of an octave such as
a half-octave or a third-octave. In a preferred embodiment having
thirteen diode trains, the filters 24 and corresponding diode
trains carry out the following filter functions.
______________________________________ Diode Train Frequency Range,
Hertz ______________________________________ 1 2-4 2 4-8 3 8-16 4
16-31 5 31-62 6 62-125 7 125-250 8 250-500 9 500-1000 10 1000-2000
11 2000-4000 12 4000-8000 13 8000-16,000
______________________________________
The amplitude lines are calibrated in useful mechanical vibration
units such as mils (thousandths of inches of mechanical
displacement), inches per second; g's (gravitational constant); or
voltage (decibels). The parameters of the circuitry are selected to
yield the desired calibration units.
Operation
The operator assembles the mechanical vibration analysis apparatus
and particularly the vibration detector 11 and signal conditioner
13 in suitable physical relationship to the rotor 10 under
investigation. As the rotor is turning at a selected speed, usually
its normal operating speed, the switch 17 has its switch arm 17c
contacting terminal 17b, i.e., the filter 15 is bypassed. The
octave band filter 21 will provide to the operator an instantaneous
visible display of the relative magnitude of mechanical vibration
in each of the selected frequency bands A, B, C, D, E, F, G. The
display may take on several forms of presentation as shown in FIGS.
2, 3, 4 which are plan views of a typical visible display of
illuminated diodes as seen through a translucent glass plate of the
display device. In FIG. 2, only one diode in each of the trains A-G
is illuminated at each instant. In FIG. 3 all of the diodes below a
selected diode in each train are illuminated at each instant. In
FIG. 4 one or occasionally two sequential diodes in each train are
illuminated at each instant.
The operator by inspecting the visible display as seen in FIGS. 2,
3, 4 can determine which frequency band is experiencing maximum
mechanical vibration and can quickly direct attention to that high
amplitude frequency range.
Filter Fine Tuning
When the vibration analyzer 19 employs an observation device 20
which does not include a scale deflecting meter but instead employs
a digital readout presentation, the present device provides
simplified tuning of the filter 15. The filtering is achieved with
the switch 17 having its switch arm 17c in contact with the
terminal 17a. In this presentation the vibration signal from the
signal conditioner 13 is delivered through conductor 14. A selected
band of frequencies is passed through the filter 15 along conductor
16, switch 17, conductor 18 to the analyzer 19. The precision of
the analyzer 19 is enhanced when the filter 15 has its passband
centered at the frequency of peak vibration phenomena. The signal
from the conductor 16 is delivered through the switch 17 and
conductor 22 to the octave band analyzer 21. Depending upon the
frequency at which the filter 15 is tuned, one or more of the
filters 24 will pass electrical signals to one or more of the
related diode trains A, B, C, D, E, F, G. The operator can
selectively adjust the passband of the filter 15 by observing peak
indications on the appropriate diode train and thereby achieve
visually and manually a fine tuning of the filter 15 to optimize
the results obtained in the vibration analyzer 19.
* * * * *